Arum says UFC alone should be blamed if fight between McGregor and Mayweather does not take place.

The Ultimate Fighting Championship (UFC) want half of Conor McGregor's purse if the promotion have to allow their lightweight champion to face Floyd Mayweather in a boxing fight, Bob Arum has claimed.

McGregor last stepped into the octagon when he defeated Eddie Alvarez at UFC 205 and since then he has been on break until the birth of his first child. The Dubliner and the boxing legend have been involved in a war of words as the duo are edging closer in signing dotted lines.

The 28-year-old Irishman has a contract with the UFC and still has four fights left with the company on his current deal. The promotion's president Dana White had earlier dismissed suggestions that the boxing bout between the pair is unlikely to take place.

However, White recently explained as to why the UFC star and the retired boxer could face eachother in a one-off match in the ring. Arum, who is a legendary boxing promoter, who markets stars like Manny Pacquiao and Vasyl Lomachenko, claims that only UFC should be blamed if the fight does not take place.

"I think the only impediment there is the UFC, because UFC doesn't treat fighters the same way that boxing promoters do. In other words, UFC fighters get so much less than boxers do," Arum told FightHub, as reported by The Sun.

"They proposed a deal to Conor that on his share of the purse, they take 50 percent. Now, give me a break.

"If the fight doesn't happen - not that I think it's going to be a great fight, because I think Conor fighting Mayweather is not really a fight, if it's boxing. "Conor is a great MMA fighter, but hasn't shown anything in boxing. And Mayweather's one of the great fighters. But if that fight doesn't happen, the blame will only be on the UFC," he said.